[jira] [Comment Edited] (CASSANDRA-10243) Warn or fail when changing cluster topology live

["Paulo Motta (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-10243?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15014921#comment-15014921 ] 

Paulo Motta edited comment on CASSANDRA-10243 at 11/20/15 1:08 AM:
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Nice work! I haven't finished reviewing everything but here are some preliminary comments in case you want to address before the timezone flip: 

* Is it necessary to check if a node is in dead state for the purpose of this snitch check? In my understanding, if a node is on a dead state, it's neither live nor member of the ring, so I didn't get why that check was done previously on getLiveTokenOwners() in the first place, do you know? Maybe historical reasons? I'd prefer to have a simpler isLiveMember() check on StorageService (since it checks both gossip and tokenmetadata), and this method would basically return Gossiper.isLiveEndpoint(endpoint) && tokenMetadata.isMember(ep), but this is a personal thing so it's up to you to take this suggestion.
* Did you intend to decrease the default snitch configuration refresh period from 60 to 5 seconds?
* On {{GossipingPropertyFileSnitch}} I think it's only necessary to check if the dc/rack changed, or do you see a situation where one would want to live change the rack/dc of a non-ring memmber?
* Also on the {{GossipingPropertyFileSnitch}} maybe it's not necessary to updateTopology/invalidateCachedRing, since topology change is not allowed anymore?

I'm not sure if this should go into 2.1 or 2.2, since we're already towards the end of line on 2.1, so it could be a bit risky to do a major change on the snitches at this point, but on the other hand CASSANDRA-10242 (which is already on 2.1) wouldn't make much sense without this. Do you have any suggestions if this should go on 2.1 or 2.2 [~tjake] [~iamaleksey] ?

I will follow-up with more comments later (if there are any).


was (Author: pauloricardomg):
Nice work! Some preliminary comments in case you want to address before the timezone flip: 


> Warn or fail when changing cluster topology live
> ------------------------------------------------
>
>                 Key: CASSANDRA-10243
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-10243
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Tools
>            Reporter: Jonathan Ellis
>            Assignee: Stefania
>            Priority: Critical
>             Fix For: 2.1.x
>
>
> Moving a node from one rack to another in the snitch, while it is alive, is almost always the wrong thing to do.



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